CVE-2019-12749 : Exploit Details and Defense Strategies
Learn about CVE-2019-12749, a vulnerability in dbus versions before 1.10.28, impacting Canonical Upstart in Ubuntu 14.04. Find out the impact, affected systems, exploitation mechanism, and mitigation steps.
A vulnerability in dbus versions before 1.10.28, 1.12.x before 1.12.16, and 1.13.x before 1.13.12 impacted Canonical Upstart in Ubuntu 14.04. This vulnerability allowed for cookie spoofing through symlink mishandling in the DBusServer component.
Understanding CVE-2019-12749
This CVE involves a vulnerability in the DBusServer component used in Canonical Upstart in Ubuntu 14.04, affecting certain uses of dbus-daemon.
What is CVE-2019-12749?
The vulnerability in dbus versions before 1.10.28, 1.12.x before 1.12.16, and 1.13.x before 1.13.12 allowed for cookie spoofing through symlink mishandling in the DBusServer component.
The Impact of CVE-2019-12749
The vulnerability could be exploited by a malicious client with write access to its home directory, enabling unauthorized read and write access in unintended locations. This could lead to authentication bypass and potential misuse of user IDs.
Technical Details of CVE-2019-12749
This section provides more technical insights into the vulnerability.
Vulnerability Description
The vulnerability in dbus versions before 1.10.28, 1.12.x before 1.12.16, and 1.13.x before 1.13.12 allowed for cookie spoofing through symlink mishandling in the reference implementation of DBUS_COOKIE_SHA1 in the libdbus library.
Affected Systems and Versions
- Versions before 1.10.28, 1.12.x before 1.12.16, and 1.13.x before 1.13.12
- Canonical Upstart in Ubuntu 14.04
Exploitation Mechanism
- Required a malicious client with write access to its home directory
- Manipulation of a specific symlink, "~/.dbus-keyrings"
- Allowed unauthorized read and write access in unintended locations
Mitigation and Prevention
Protecting systems from CVE-2019-12749 requires immediate actions and long-term security practices.
Immediate Steps to Take
- Apply relevant security updates and patches promptly
- Monitor and restrict write access to critical directories
- Implement strong authentication mechanisms
Long-Term Security Practices
- Regular security audits and vulnerability assessments
- Educate users on safe symlink handling practices
- Implement least privilege access controls
Patching and Updates
- Update to versions 1.10.28, 1.12.16, or 1.13.12 to mitigate the vulnerability